Shock proof watchcase

ABSTRACT

A shock-proof watchcase having a shock-absorbing member supported between the case body and back cover. The watch movement is mounted on said shock-absorbing member. The shockabsorbing member is adapted to absorb shocks both in the axial and transverse directions of the watch.

United States Patent 91 Fujimori et al.

111 3,727,367 [451 Apr. 17, 1973 [s41 SHOCK PROOF WATCHCASE [76] Inventors: Yoshiaki Fqjimori, 3091-1, Konami; Ikuo Tokunaga, 3-5, 3-chome, both of Suwa, Japan [22] Filed: Oct. 7, 1971 [21] App]. NO.: 187,261

[30] Foreign Application Priority Data Oct. 8, 1970 Japan ..45/87857 [52] US. Cl. ..58/88 C, 58/94 [51] Int, Cl. ..G04b 37/04 [58] Field of Search ..58/88 R, 88 C, 90 R, 58/94 [56] References Cited UNITED STATES PATENTS 5,643,424 2 172 Simon ..58/90 R 3,492,810 2/1970 Levrat ..58/90X 2,256,200 9/I94l Heilman ..58/94X FOREIGN PATENTS OR APPLICATIONS 721,920 1/1955 Great Britain ..'.58/90 R Primary ExaminerGeOrge H. Miller, Jr. AttorneyAlex Friedman et a1.

[ 5 7 1 ABSTRACT A shock-proof watchcase having a shock-absorbing member supported between the case body and back cover. The watch movement is mounted on said shock-absorbing member. The shock-absorbing member is adapted to absorb shocks both in the axial and transverse directions Of the watch.

8 Claims, 3 Drawing Figures PATENIE APR a 71m -1 367 SHEET 1 [1F 2 PATENTEDAPR 1 7 :373

SHEET 2 [IF 2 FIG. 3

BACKGROUND OF THE INVENTION This invention relates generally to shock-proof watchcase constructions for watches. In the known shock-proof devices, shock-proof bearings are provided at portions of the watch movement particularly susceptible to shocks, such as the axis of the balance, so that, for example, the axis of the balance cannot be disabled'and the watch movement cannot be stopped, even if the watch is subjected to shock. However, in such prior art arrangements, a plastic deformation occurs in the hair spring of the balance which has substantial influence on the time-keeping accuracy of the watch. In addition, several screws in the watch movement tend to become loosened. The errors in timekeeping accuracy caused by such shocks are relatively large, and cannot be avoided in the known shock-proof arrangements. The shock-proof bearings utilized are not strong enough to prevent the hair spring of the balance from being subjected to plastic deformation. Thus, the conventional shock-proof arrangements cannot protect a watch against outside shocks to the extent necessary to prevent errors in time-keeping accuracy.

SUMMARY OF THE INVENTION Generally speaking, the shock-proof watchcase according to the invention includes a shock-absorbing member formed of rubber, a synthetic resin, a plate spring or the like, and mounted between the case body and the case back. The watch movement is supported on said shock-absorbing member, said shock-absorbing member being adapted to absorb shocks in both the axial and the transverse directions of said watch. A

separate supporting-ring member may be provided for carrying said watch movement, shock-absorbing elements being positioned intermediate said supportingring member and both said case body and said case back to suspend said supporting-ring member and case movement in spaced relation to both said case body and said case back.

Accordingly, it is an object of this invention to eliminate inaccuracies in time-keeping caused by shocks. More specifically, it is an object of the present invention to avoid the plastic deformation of the hair spring of the balance due to shock, thereby avoiding time-keeping inaccuracies. A further object of the invention is to provide a shock-proof watchcase wherein the watch movement is supported in spaced relation to both the case body and case back by shock-absorbing elements.

Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.

The invention accordingly comprises the features of construction, combinations of elements, and arrangement of parts which will be exemplified in the constructions hereinafter set forth, and the scope of the invention will be indicated in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS For a fuller understanding of the invention, reference is had to the following description taken in connection with the accompanying drawings, in which:

FIG. 1 is a partial sectional view showing one embodiment of the shock-proof watchcase according to v DESCRIPTION OF THE PREFERRED EMBODIMENTS In general, taking into consideration the influence of deformation on the hair spring when shocks are applied to a watch from the outside, the deformation in the vibratory direction of the hair spring or transverse direction of the watch (X direction) is greater than the deformation in the axial direction of the watch balance (Y direction). The arrangement according to the invention is adapted to take advantage of these characteristics by gradually absorbing the momentary shock force exerted in the vibratory direction of the hair spring (X direction) through a shock-absorbing member mounted between the watch movement and the watchcase. In this manner, deformation in the vibratory direction of the hair spring cannot occur.

I Referring now to FIG. 1, the wristwatch according to the invention includes a case body 1. A supporting ring 2 having an elastic projecting portion 2a formed as a unit therewith on the upper side thereof engages and supports a watch movement 5. Said watch movement and supporting ring are positioned and supported within case body 1 by means of a shock-absorbing ring or partial ring member 3 formed of a synthetic resin or a hard rubber. A further shock-absorbing member 4 formed of a relatively soft synthetic resin or rubber is positioned intermediate supporting ring 2 and a case back 6. Said case back is threadably engaged in case body 1 and cooperates with said case body to support and suspend the movementS by means of the shockabsorbing rings 3 and 4 and the supporting ring 2. The watch also includes a crystal 7 engaged against case body 1 by means of a tension ring 8, and a watch dial 9.

The watch movement 5 and supporting ring 2 are suspended in spaced relation relative to case body 1 and case back 6, as indicated by the intervals a, b, d, and e. In the horizontal, or transverse, direction the width of intervals a is larger than the width of intervals b, so that the movement cannot directly hit against the case. Even in the face of extreme vibration, only the supporting ring would engage the case body. In the vertical, or axial, direction the width of interval e is larger than that of interval d, so that the movement cannot directly hit against the case back even if subjected to maximum deformation. In such circumstances, the supporting ring would strike against said case back. The width of interval 0 is larger than that of interval d, in order to ensure that shock-absorbing member 3 is not displaced and disengaged from the case body surface 1a.

In the shock-absorbing watchcase according to the invention, the watch movement is normally positioned and fixed by the shock-absorbing member 3 against the case body. Shocks in the X direction, as shown in FIG. 1, are gradually absorbed so as to weaken the operating force on the hair spring and balance wheel. On the other hand, shocks in the Y direction are principally absorbed by shock-absorbing member 4, with shock- An alternate embodiment is shown in FIG. 2,-

wherein the supporting ring and the shock-absorbing member 11 are formed as a unit, making assembly even easier. The shock-absorbing member 3 and the shock-absorbing member 4 may be formed as a unit as shown by shock-absorbing member 12 of FIG. 3. In the embodiment of FIG. 3, the shock-absorbing member is formed of a thinmetal plate and the fixed surfaces of the case body and case back against which said shockabsorbing member engages are inclined to obtain a vibratory displacement in the up and down, or axial, direction when shocks are applied; The watch movement is positioned and fixed relative to the inclined surfaces of the case body and case back through the shock-absorbing member 12 by the uniform force applied to the shock-absorbing member by the watchcase. When a shock force is applied in the horizontal, or

transverse, direction, the effect is the same as in the embodiments of FIGS. 2 and 3. When the shock force is applied in the vertical, or axial, direction, the shockabsorbing member is displacedand absorbs the shock force.

Referring to FIG. 3, a projecting portion 13a provided at certain locations in the outer peripheryof supporting ring 13. Corresponding apertures are formedin the shock-absorbing member 12, which may be formed of a synthetic resin or a plate spring. The shock-absorbing member and the supporting ring are fixed together by positioning theprojecting portions within said apertures.

The watchcase according to the invention is particularly adapted to absorb shocks in, the vibratory direction of the watch hair spring, a feature not found in the known. shock-proof watchcaseconstructions. Further, the watchcase construction according to the invention is readily assembled from a minimum of parts, thereby resulting in improved production charac- I case body and case back.

- said supporting ring and said case back.

are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

What is claimed is: I 1. A shock-proof watchcase comprising a case body;

a case back adapted for cooperative engagement with said case body; a watch movement; a supporting ring engaged against the periphery of said watch" movement for supporting said watch movement; and shock-absorbing means intermediate said supporting ring and each of said case body and case back, said supporting ring, shock-absorbing means, case back and case body being dimensioned for clearance between said supporting ring and watch movement on the one hand and said case back and case body on the other hand in both the axial and transverse directions of said watchcase so that both axial and transverse shocks may be absorbed.

2. A shock-proof watchcase as recited in claim 1, wherein said shock-absorbing means includes shockabsorbing portions projecting substantially in said axial direction for respective engagement by said case body and case back.

3. A shock-proof watchcase as recited in claim 2,

wherein-said supporting ringand said shock-absorbing portions of said shock-absorbing means are dimensioned so that said watch movement is spaced a greater distance from said watchcase and watch back than said supporting ring, said supporting ring being formed at leasfin part of a resilient material for absorbing the shock force of any engagementthereof against said 4. A shock-proof watchcase as recited in claim 2',

wherein at least one of said shock-absorbing portions is formed as a separate element mounted intermediate 5. Ashock-proof watchcase as recited in claim 4, wherein at least the shock-absorbing portion engaging said case back is formed as a separate element, and is formed of a material having greater resiliency than the material of the shock-absorbing portion engaging said case body.

6. A shock-proof watchcase as recited in claim 2, wherein said shock-absorbing portions are formed as an axially extending plate member engaged between said case body and case back, said shock-absorbing means including means for supporting said supporting ring on said plate member.

7. A shock-proof watchcase as recited in claim 6, wherein the respective surfaces of said case body and case back against which said plate member engages are inclined, said plate member being formed of a thin formed of a thin synthetic resin. 

1. A shock-proof watchcase comprising a case body; a case back adapted for cooperative engagement with said case body; a watch movement; a supporting ring engaged against the periphery of said watch movement for supporting said watch movement; and shockabsorbing means intermediate said supporting ring and each of said case body and case back, said supporting ring, shockabsorbing means, case back and case body being dimensioned for clearance between said supporting ring and watch movement on the one hand and said case back and case body on the other hand in both the axial and transverse directions of said watchcase so that both axial and transverse shocks may be absorbed.
 2. A shock-proof watchcase as recited in claim 1, wherein said shock-absorbing means includes shock-absorbing portions projecting substantially in said axial direction for respective engagement by said case body and case back.
 3. A shock-proof watchcase as recited in claim 2, wherein said supporting ring and said shock-absorbing portions of said shock-absorbing means are dimensioned so that said watch movement is spaced a greater distance from said watchcase and watch back than said supporting ring, said supporting ring being formed at least in part of a resilient material for absorbing the shock force of any engagement thereof against said case body and case back.
 4. A shock-proof watchcase as recited in claim 2, wherein at least one of said shock-absorbing portions is formed as a separate element mounted intermediate said supporting ring and said case back.
 5. A shock-proof watchcase as recited in claim 4, wherein at least the shock-absorbing portion engaging said case back is formed as a separate element, and is formed of a maTerial having greater resiliency than the material of the shock-absorbing portion engaging said case body.
 6. A shock-proof watchcase as recited in claim 2, wherein said shock-absorbing portions are formed as an axially extending plate member engaged between said case body and case back, said shock-absorbing means including means for supporting said supporting ring on said plate member.
 7. A shock-proof watchcase as recited in claim 6, wherein the respective surfaces of said case body and case back against which said plate member engages are inclined, said plate member being formed of a thin metal plate.
 8. A shock-proof watchcase as recited in claim 6, wherein the respective portions of the surfaces of said case body and case back against which said plate member engages are inclined, said plate member being formed of a thin synthetic resin. 